However the song is heard all over the world, the Japanese never mind it, by right, don't know it.

But meanwhile, actually it's Korean boom in Japan, so why "Gangnam Style" can't be boom, too? The reason is, I think, PSY wasn't promoted in Japan. I know he wasn't being promoted in other countries, but in Japan the song sold well is one in fully prepared such as Girls Generation, KARA, TVXQ.